CAPTCHAs work by presenting users with a challenge that is easy for humans to solve but difficult for computers. The most common type of CAPTCHA is the visual CAPTCHA, which displays a series of distorted or pixelated letters and numbers. The user is required to enter the code correctly to pass the test. Other types of CAPTCHAs include audio CAPTCHAs, which play an audio clip, and behavioral CAPTCHAs, which monitor user behavior.

Solving CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart) is one of the most accessible entry-level online jobs in India. Because it requires no specialized skills or financial investment, it is a popular choice for students, homemakers, and those looking for modest supplemental income.